Drawing compound



Patented Mar. 27, 1934 PATENT OFFICE DRAWING COMPOUND Walter B. Craig, Detroit, Mich., assignor to Packard Motor Car Company, Detroit, Mich, a corporation of Michigan No Drawing. Application February 26, 1931,

SerialNo. 518,597

6 Claims.

The present invention relates to drawing compounds, that is, to lubricants employed to facilitate drawing operations.

Many compounds or mixtures of various lubri- 5 cants for use in metal drawing processes have heretofore been suggested, and numerous such compositions have been put into actual use. As the frictional forces developed between drawing dies and the blanks being operated upon vary considerably in accordance with the nature of the drawing operation and the character of the material being fabricated, it has been found advantageous to employ lubricants of different characteristics in connection with specifically different drawing operations. Thus, for drawing light metals such as aluminum, kerosene and vaseline have been suggested as being quite sufficient, while for drawing sheet steel into various shapes, involving operations which develop heavy pressures and proceed only at low velocities, it has generally been considered essential to use a lubricant having a heavy body in order to keep the surfaces between which the lubricant is introduced from coming into contact. Lubricants heretofore employed in steel drawing processes have, for instance, generally included large proportions of graphite and heavy greases.

The present invention contemplates improvements in drawing compounds or lubricants of general utility, but particularly it comprehends improvements in lubricants to be employed in drawing steel sheets, plates, strips, etc., into desired form, operations which require heavy pressures and in which the drawing operation proceeds at relatively low velocities.

In the automotive industry, verylarge quantities of sheets, generally of mild steel, are drawn into various shapes in the formation of automobile bodies. For instance, fenders, body 40 plates, seats, and the like are all formed by drawing steel plates into the necessary shapes. Some of these shapes can only be formed by relatively deep drawing operations, thus increasing the magnitudes of the pressures which must necessarily be employed and rendering it difiicult to produce the articles without considerable danger of breakage and buckling of the metal.

I have discovered that improved results can be obtained in drawing operations by the use of a 50 compound comprising essentially a syrupy hydrocarbon, such as corn syrup, which may be employed either alone or in conjunction with other liquids or solids, or liquids and solids hereinafter further described.

Other syrupy carbohydrates which are satisfactory include maple syrup and starch syrup, both containing glucose.

The syrupy material is preferably but not necessarily used in conjunction with a filler material, such as diatomaceous earth, and a diluent, such as water. The quantities of each component employed are dependent upon the nature of the stampings with which the composition is to be employed. Also syrups of different specific gravity may be used to produce compositions of desired viscosity and other properties.

The diluent may be of a nature which merel serves to cheapen the cost of the composition, such as water, or it may be a substance having some beneficial efiect upon the metal parts with which it comes in contact, such as liquids which aid in the removal or prevention of rust.

The filler material may be any substance which serves to thicken or give body to the syrupy carbohydrate-diluent mixture and includes such substances as diatomaceous earth, fullers earth, clay soapstone, and whiting.

The filler is preferably one which will remain suspended in the syrup mixture. Such compounds as starch and flour may be employed where the drawing compound is to be used within a short time after its production.

The filler is preferably used in an extremely finely divided condition and, if not already in such condition, is ground to the desired fineness in any suitable manner either before or after the mixing operation, the mixing itself being efiected in any desired way.

A composition found to be particularly suitable for drawing deep stampings is composed of 70% of 43 B. corn syrup, 15% of 000 multicel infusorial earth, and 15% of water.

It is to be understood that the above propor tions are given only by way of example and that they may be varied within wide limits without departing from the scope of the instant invention. -In addition to these constituents, there may be added substances which give a color or a pleasant scent to render the product more attractive or salable.

The composition of the present invention is applied between the dies and the blanks in an obvious manner. It has been found that a single application will serve for several stampings. After a number of stampings have been effected, it will become necessary, as usual with other lubricants, to remove the spent lubricant from the dies. This may be accomplished -..by merely washing with water. Because of this feature, the use of the water soluble lubricants is a further distinct advantage over the use of graphite and grease in drawing steel, such lubricant being insoluble and removable only with difficulty.

While I have disclosed my improved drawing compound or lubricant in several of its specific forms, it will be appreciated that the invention is by no means limited to the exact compositions set forth by way of example, the compound be-- ing susceptible of considerable variation in the selection of the minor ingredients thereof and in the percentage 'of its component elements in adapting the same to facilitate drawing operations of different character and metals of different composition.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:-

1. A liquid drawing compound for use in the shaping of metallic sheets and the like under pressure in shaping dies comprising a solution containing a syrupy carbohydrate as its principal ingredient, said compound having the capacity to remain liquid during a drawing operation.

2. A liquid drawing compound for use in the shaping of metallic sheets and the like under pressure in shaping dies comprising a solution containing corn syrup as its principal ingredient, said compound having the capacity to remain liquid during a drawing operation.

3. A liquid drawing compound for use in the shaping of metallic sheets and the like under pressure in shaping dies comprising a solution containing maple syrup as its principal ingredient, said compound having the capacity to ,remain liquid during a drawing operation.

4. A liquid drawing compound for use in the shaping of metallic sheets and the like under pressure in shaping dies comprising a solution containing starch syrup as its principal ingredient, said compound having the capacity to remain liquid during a drawing operation.

5. A liquid drawing compound for use in the shaping of metallic sheets and the like under pressure in shaping dies comprising a solution containing a syrupy carbohydrate as its principal ingredient and also containing as a minor constituent a filler material selected from the group of substances including infusorial earth, fullers earth, clay, soapstone, and whiting, said compound having the capacity to remain liquid during a drawing operation.

6. A liquid drawing compound for use in the shaping of metallic sheets and the like under pressure in shaping dies comprising approximately 70% corn syrup, approximately 15% infusorial earth, and approximately 15% water, said compound having the capacity to remain liquid during a drawing operation.

WALTER B. CRAIG. 

